Insulation material and a method to produce

Abstract

The present disclosure relates to an insulation material for a conductor bar of an electric machine. An object of the invention is to provide for an alternative insulation material in the field of electric machines. The object is solved by an insulation material for a conductor bar for an electric machine comprising glass-ceramic flakes made from a heat treated silica glass precursor in the shape of flakes. Further disclosed are a corresponding method and the use of glass-ceramic flakes as an insulation material for a conductor bar of an electric machine.

What is claimed is: 
     
       1. An insulation material for an electric machine comprising:
 a polycrystalline glass-ceramic flake material comprising an inorganic component having around 40% to 80% crystallinity with a thermal conductivity greater than about 0.5 W/mK, or a coefficient of thermal expansion greater than about 11×10 −6  K −1  between about 25 and 200° C., effective for insulating a conductor bar in an electric machine. 
 
     
     
       2. The insulation material according to  claim 1 , wherein the polycrystalline glass-ceramic flake material comprises a proportion of residual amorphous glass. 
     
     
       3. The insulation material according to  claim 2 , wherein the polycrystalline glass-ceramic flake material comprises a crystal phase lithium zinc silicate, lithium metasilicate, lithium disilicate, quartz, cristobalite, or tridymite. 
     
     
       4. The insulation material according to  claim 3 , wherein the polycrystalline glass-ceramic flake material is produced from a glass precursor comprising silica, lithium oxide, zinc oxide, and phosphorous pentoxide melted in air at about 1300° C. 
     
     
       5. The insulation material according to  claim 3 , wherein the polycrystalline glass-ceramic flake material is produced from a first glass precursor comprising silica, lithium oxide, zinc oxide, and phosphorous pentoxide and a second glass precursor comprising silica, lithium oxide, zinc oxide, potassium oxide, and phosphorous pentoxide melted in air at about 1400° C. 
     
     
       6. The insulation material according to  claim 1 , wherein the inorganic component has around 80% crystallinity. 
     
     
       7. The insulation material according to  claim 1 , wherein the inorganic component has around 40% crystallinity. 
     
     
       8. The insulation material according to  claim 1 , wherein the inorganic component has around 44% crystallinity. 
     
     
       9. A material comprising:
 polycrystalline glass-ceramic flakes comprising an inorganic component having around 40% to 80% crystallinity with a thermal conductivity greater than about 0.5 W/mK, or a coefficient of thermal expansion greater than about 11×10 −6  K −1  between about 25 and 200° C., produced by heat treating amorphous flakes to a temperature effective for polycrystalline structure formation; and 
 the amorphous flakes comprise a first silicate glass composed of silica, lithium oxide, zinc oxide and phosphorus pentoxide and a second silicate glass composed of silica, lithium oxide, zinc oxide, potassium oxide and phosphorus pentoxide. 
 
     
     
       10. A method to produce an insulation material comprising:
 heat treating a silicate glass flake comprising amorphous flakes obtained by heating a first silicate glass and a second silicate glass, to obtain a glass-ceramic flake material; 
 wherein the first silicate glass is composed of silica, lithium oxide, zinc oxide and phosphorus pentoxide, and the second silicate glass is composed of silica, lithium oxide, zinc oxide, potassium oxide and phosphorus pentoxide. 
 
     
     
       11. The method of  claim 10 , wherein the obtained glass-ceramic flake material is polycrystalline. 
     
     
       12. The method of  claim 10 , wherein at least one of the heating of the first silicate glass and the second silicate glass, or the heat treating of the silicate glass flake results in a residual amorphous glass, wherein the insulation material comprises a proportion of the residual amorphous glass.